The human body can be trained to carry out specific physical motions or activities through the guided procedure of repeating approximations of the desired behavior. In the field of rehabilitation, persons who have lost neuromuscular functions can relearn how to carry out such basic activities as grasping and walking, as well as more complex motions, through the process of repetition. In the recreational field, skilled players learn through repetition to carry out critical motions in the fields of tennis, basketball, golf and baseball to high degrees of precision.
It is known to train individuals to carry out a kinesthetic procedure by providing feedback which is indicative of their level of performance and progress towards achieving full competence in respect of the subject activity. A number of references in this regard are:                U.S. Pat. No. 6,413,190 to Wood et al        U.S. Pat. No. 6,032,530 to Hock        U.S. Pat. No. 5,989,157 to Walton        U.S. Pat. No. 5,692,517 to Junker        U.S. Pat. No. 5,679,004 to McGowan et al.        U.S. Pat. No. 5,697,791 to Nashner et al.        U.S. Pat. No. 5,277,197 to Church        U.S. Pat. No. 4,571,682 to Silverman, et al.        U.S. Pat. No. 3,905,355 to Brudney        U.S. Pat. No. 3,641,993 to Gaarder        
Such training has been effected through the use of body sensors that provide signals corresponding to specific body motions and stances. Such kinesthetic sensors can include goniometers, inclinometers, rotational sensors, force sensors, torsiometers, position sensors, bend sensors, tilt sensors, stretch sensors, pressure sensors, force sensors, velocity sensors, accelerometers, and neuromuscular electromyographic (EMG) pick-ups which identify the activation of specific muscles or muscle groups. Any sensor which can provide an indication as to the performance of a physical activity by the human body arising from the activation of specific muscles or muscle groups is relevant in this field. Hereafter such sensors are referred to as “body sensors.
A particular challenge in this field is to train multiple, distinct, body actions to operate on a coordinated basis. An example of such a movement that could be optimized through bio-kinesthetic feedback would be the case of a person learning to swing a tennis racket. Such a person may have a pressure pad placed under one, forward, foot and an inclinometer strapped to their wrist. In order to train the individual to rotate their wrist at the same time that their weight is shifted onto the forward foot, trainees are coached to carry out the motion of swinging a tennis racket while the feedback originating from the two sensors is presented to them by a suitable display.
Various types of displays to provide feedback to trainees have been proposed. One of the simplest is the creation of an image on a computer screen that presents a bar which lengthens in accordance with the value of the output originating from a body sensor. Such scalar values arise from detecting the output of a single sensor.
One particular prior art system described in part in U.S. Pat. No. 6,413,190 to Wood et al relies upon creating a video display which provides feedback to a trainee, indicating the progress that is being made towards achieving competence in a specific physical activity. Feedback is provided through the positioning of a cursor on a video screen which serves as part of a video game. Integration of this type of display into the field of kinesthetic training provides motivation for trainees to deliver appropriate signals from a body sensor and trains them to carry out an activity based on that sensor with the effort or timing necessary to acquire a functional skill.
This reference U.S. Pat. No. 6,413,190 to Wood et al teaches use of a video game such as “Pong”™, which was one of the earliest video games created for home computers. In this game a cursor in the form of a reflecting wall is moved by the game player along one edge of the screen to intersect the image of an arriving ball. The presence of the reflecting wall or “paddle” causes the ball to rebound and eventually return for a second potential interception. According to this prior art patent, the output from a body sensor is used to control the position of the reflecting wall or paddle on the video screen in various ways. For example, body sensor output above a selected threshold releases the paddle to move across a border of the screen. In the absence of a signal, the paddle may remain stationary or, in one version, move automatically to return to a “parked” location. Alternately, the paddle may move proportionally to the output from the body sensor.
In this Wood reference a body sensor provides an output in the form of a scalar value which, when such output surpasses a preset threshold, allows the trainee to exercise control and participate in the videogame. Outputs below this threshold produce no response. Further, the use of multiple body sensors is disclosed. This patent references using the output from at least two sensors to control cursor movement on the video screen. Such control can be in both X and Y directions, encouraging the trainee to manipulate the cursor as part of a video game by actuating two body sensors. However, the outputs from such multiple X, Y sensors have separate, independent effects on the display.
Two types of displays arising from the output from a single sensor can be contemplated. The first is an “on-off” display wherein achievement of a minimum level of signal, over a preset threshold, releases a paddle for motion on a video display. The second is a “proportional” display wherein the position of a paddle on a video display is proportional to the intensity of the signal being generated by the body sensor.
The claims of this patent are directed towards combining signals obtained from first and second muscle contractions by processing such signals on the basis of “Boolean anding”. Thus the position of a gamepiece within a computer game is controlled on the basis that the user must effect two muscle contractions in order to move the gamepiece on the display. Alternately, one sensor must generate a “null” output for Boolean anding to permit gamepiece movement. Nevertheless, two sensors are always being monitored and their combined outputs release the paddle for motion in an on-off manner.
However, this reference does not teach that the signal strengths from the respective sensors are mixed. It therefore falls short of producing a “composite” output. Rather, Boolean anding only says that the outputs of two sensors have to be monitored in order to achieve action in the video display.
This patent teaches that output signals from body sensors can be adjusted in magnitude so as to size them to fit a video display screen, a process that may be referred to as “calibration” or “normalization”. Thus the system can establish upper and lower range limits of signal that fit within the boundaries of the video display screen. The upper and lower limits of the signal from the sensor can be converted to represent a scale from 0 to 100%. The signal presented as the person performs a muscle contraction or movement can thereby be adjusted to fall within this range.
This patent further teaches that an output may be suppressed until a certain threshold level, controlled by a therapist, has been achieved. Movement of the game piece can be made non-responsive unless the person providing the body signal exceeds a selected level of output. This can provide an incentive for effort as, for example, in the case where the threshold is set near the upper limit of a person's capacity.
A therapist can adjust the limits while the patient is engaged in a therapy exercise, i.e. moving the goal posts during the game. Thus this reference observes that as the patient's movements are improved, the settings can be gradually changed to require more effort by the patient in order to achieve a given activation of the cursor on the screen.
Use of a central dead-band has also been established. Thus crossing one of two thresholds would be required to move a cursor right or left, with no cursor motion resulting from a body position within the dead band between the two thresholds. Different sensors can have different limits and different thresholds.
Cursor control can either be based on a position correspondence or a velocity correspondence. Thus, in one embodiment, if the angle formed by elbow were midway between the two extremes, then the game piece position would be midway between the two extreme sides of the display. In another embodiment, the game piece position is set by putting the game piece in motion in a specific direction corresponding to the current position of a body part.
A non-linear correspondence between sensor output and display is proposed as a possibility in Wood. This permits a magnified or de-magnified response in certain ranges. Thus, in some embodiments, cursor movement is not linearly related to body movement. For example, movement in the middle of the range may cause very little corresponding cursor movement while movement towards one extreme or the other of the range may cause a greater amount of corresponding movement in the display. This feature addresses the form of display associated with a single output. It does not address the treatment of multiple outputs to produce a single display.
A further type of pre-existing video display presents the signal values originating from a single force sensor in an X-Y graphic format. The Y direction represents the strength of the signal and the X direction represents time, providing a trace which proceeds across the screen. By scrolling the screen to the left, the leading end of the trace remains continuously present on the screen, while the recent history of the values being presented are shown by the trailing balance of the trace.
As a further feature of this specific pre-existing type of video display, the difference between the output values of two force sensors has also been displayed as a single trace on such screen. Thus a composite signal has been created by subtracting the value of the output from one force sensor from the value of the output from another force sensor. If the object were to train a subject to produce balanced forces on two force sensors, as with dual force pads placed beneath a subject's respective feet, then this difference-based composite trace, when this objective is achieved, would present a steady, horizontal, line having a value of zero on the vertical scale.
U.S. Pat. No. 6,032,530 to Hock is such a case where feedback based upon a differential between signals is provided to an individual who is trying to learn a physical activity. This document refers to separate sensors being combined by providing: “a sensor system for sensing rotational kinetic activity . . . (wherein) . . . The outputs of the sensors are connected differentially for measuring rotation of the section about the axis.” While this reference suggests a mixing of signals from two symmetrically placed sensors, this reference does not teach producing a composite output for purposes of a display that provides feedback to a patient in the form of a single indication derived from accumulating values from multiple inputs arising from non-symmetrical muscle sources.
Hock also mentions the case where many transducers may be used:
“While the system works with a single transducer, there may be multiple transducers, with processing circuitry that can integrate multiple inputs and generate a composite result as a function of the multiple inputs.
“However, in the context of the Hock disclosure the composite result he refers to appears to be directed to the production of multiple, discreet and musical notes rather than a true composite signal wherein the feedback provided does not distinguish the signals originating from individual body sensors.
While these various systems represent instances of provision of displays that can serve to provide feedback to a user, the full potential of the composite display concept has not been recognized or adequately exploited. What the prior art references fail to address is an enhanced procedure for effecting an integration of multiple outputs from the sensory-motor system to provide a single output composite display arising from different, non-symmetrical muscle origins. A need exists for a system based upon combining the outputs from two or more such sensors, particularly with the added feature of weighting values provided to such outputs, to produce a single performance-indicating output.
This invention addresses the object of providing a kinesthetic training system that provides guidance and motivation for a trainee through more advanced forms of composite displays.
This invention also addresses the object of providing a kinesthetic training system which progressively exposes a subject to the outputs of two or more sensors. This progressive training methodology goes beyond and is to be distinguished from mere “Boolean anding” in that it provides subjects with a more complex display that serves as a strong incentive for improved physical performance.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims that conclude this Specification.